An electroluminescent device does not require a backlight, has a fast response speed, and also has excellent brightness and viewing angle characteristics as it is a self-light-emitting device. In particular, an organic electroluminescent device may be manufactured in the form of a thin film with a bendable structure. Moreover, the formation of patterns and the mass production by thin film manufacturing techniques are easy, and the driving voltage is low. Furthermore, the organic electroluminescent device can theoretically emit light of all colors in a visible light region. Thus, great efforts to develop light-emitting materials used in the organic electroluminescent devices have continued. However, since blue-light-emitting materials should have a wide band gap, it is difficult to synthesize and drive the blue-light-emitting materials compared to green and red-light-emitting materials. Therefore, in order to implement the organic electroluminescent device as a natural-color flat-panel display, it is necessary to continuously develop blue-light-emitting materials with improved efficiency, color, and stability.